The present application relates generally to electrosurgical systems and methods and more particularly to electrosurgical instruments and connections between the instruments and electrosurgical units.
Surgical procedures often involve cutting and connecting bodily tissue including organic materials, musculature, connective tissue and vascular conduits. For centuries, sharpened blades and sutures have been mainstays of cutting and reconnecting procedures. As bodily tissue, especially relatively highly vascularized tissue is cut during a surgical procedure, it tends to bleed. Thus, medical practitioners such as surgeons have long sought surgical instruments and methods that slow or reduce bleeding during surgical procedures.
More recently, electrosurgical instruments have become available that use electrical energy to perform certain surgical tasks. Typically, electrosurgical instruments are hand instruments such as graspers, scissors, tweezers, blades, needles, and other hand instruments that include one or more electrodes that are configured to be supplied with electrical energy from an electrosurgical unit including a power supply. The electrical energy can be used to coagulate, fuse, or cut tissue to which it is applied. Advantageously, unlike typical mechanical blade procedures, application of electrical energy to tissue tends to stop bleeding of the tissue.
Electrosurgical instruments typically fall within two classifications: monopolar and bipolar. In monopolar instruments, electrical energy of a certain polarity is supplied to one or more electrodes on the instrument. A separate return electrode is electrically coupled to a patient. Monopolar electrosurgical instruments can be useful in certain procedures, but can include a risk of certain types of patient injuries such as electrical burns often at least partially attributable to functioning of the return electrode. In bipolar electrosurgical instruments, one or more electrodes is electrically coupled to a source of electrical energy of a first polarity and one or more other electrodes is electrically coupled to a source of electrical energy of a second polarity opposite the first polarity. Thus, bipolar electrosurgical instruments, which operate without separate return electrodes, can deliver electrical signals to a focused tissue area with a reduced risk of patient injuries.
Even with the relatively focused surgical effects of bipolar electrosurgical instruments, however, surgical outcomes are often highly dependent on surgeon skill. For example, thermal tissue damage and necrosis can occur in instances where electrical energy is delivered for a relatively long duration or where a relatively high-powered electrical signal is delivered even for a short duration. The rate at which a tissue will achieve the desired coagulation or cutting effect upon the application of electrical energy varies based on the tissue type and can also vary based on pressure applied to the tissue by an electrosurgical instrument. However, even for a highly experienced surgeon, it can be difficult for a surgeon to assess how quickly a mass of combined tissue types grasped in an electrosurgical instrument will be fused a desirable amount.
Attempts have been made to reduce the risk of tissue damage during electrosurgical procedures. For example, previous electrosurgical systems have included generators that monitor an ohmic resistance or tissue temperature during the electrosurgical procedure, and terminated electrical energy once a predetermined point was reached. However, these systems have had shortcomings in that they have not provided consistent results at determining tissue coagulation, fusion, or cutting endpoints for varied tissue types or combined tissue masses. These systems can also fail to provide consistent electrosurgical results among use of different instruments having different instrument and electrode geometries. Typically, even where the change is a relatively minor upgrade to instrument geometry during a product's lifespan, the electrosurgical unit must be recalibrated for each instrument type to be used, a costly, time consuming procedure which can undesirably remove an electrosurgical unit from service.